1. Field of the Invention
The invention relates to a method for producing a ring-shaped or plate-like element, in particular for a metal-sealing material-feedthrough, in particular for devices which are subjected to high pressures, preferably igniters for airbags or belt tensioning devices, as well as a method to produce a metal-sealing material-feedthrough.
2. Description of the Related Art
Metal-sealing material-feedthroughs are already known in various forms from the current state of the art. Metal-sealing material-feedthroughs are to be understood to be vacuum-tight fusions of sealing materials, especially glasses, glass ceramics or synthetics in metals. The metals function hereby as conductors. We refer you in this context to representative documentation U.S. Pat. No. 5,345,872, U.S. Pat. No. 3,274,937. Feedthroughs of this type are common in electronic and electrical engineering. The material used for sealing, especially glass serves as an insulator. Typical metal-sealing material-feedthroughs are constructed such that metallic internal conductors are sealed into a pre-formed sintered glass component, whereby the sintered glass component or the glass tube is sealed into an outer metal component with the so-called base body which is formed by a ring-shaped or plate-like element. Preferred applications for metal-sealing material-feedthroughs of this type are for example ignition devices. One area of application is in air bags or belt tensioning devices in motor vehicles. In this case the metal-sealing material-feedthroughs are a component part of an ignition device. The entire ignition device includes in addition to the metal-sealing material-feedthrough an ignition bridge, the explosive agent as well as a metal shrouding which tightly encloses the ignition mechanism. Either one or two, or more than two metal pins may be inserted through the feedthrough. In a preferred embodiment with one metallic pin the housing is grounded; in a preferred two-pin embodiment one of the pins is grounded.
Metal-sealing material-feedthroughs, especially for igniters for airbags or belt tensioning devices which distinguish themselves in that the feedthrough opening for the metal pins is punched out of the base body have become known from US 2006/0222881 A1, US 2004/0216631, EP-A-1 455 160, US 2007/0187934 A1 and U.S. Pat. No. 1,813,906. During the production of the base bodies from a strip stock having a thickness in the range of between 1 mm and 5 mm, preferably 1.5 mm and 3.5 mm, especially between 1.8 mm to 3.0 mm, more especially preferably between 2.0 mm to 2.6 mm the openings are punched through the entire thickness of base body D by means of a punching process, according to US 2007/0187934.
The metal pin in the sealing material is embedded into the opening punched into the base body across the entire thickness D of the base body which is in the aforementioned range.
Moreover, the feedthrough-opening in feedthroughs with more than one pin is arranged off-center according to US 2007/0187934 A1.
According to US 2007/0187934 A1 punching sheet metal has a multitude of disadvantages. One disadvantage is that when punching a solid material, for example sheet metal of the base body, a great amount of material waste occurs.
Especially in metal-sealing material-feedthroughs with two metal pins and an off-center opening the problem arose that the off-center opening resulted in a weakening of the glazing.
It is therefore the objective of the current invention, and what is needed in the art is, to avoid the described disadvantages according to the current state of the art and to cite a method in particular for the production of a base body in the form of a ring-shaped or plate-like element for a metal-sealing material-feedthrough which can be produced with lesser material waste than is the case in the current state of the art, in particular in a cold forming process.